Can required section modulus be distributed among 2 or more beams?

Question

In a case where required section modulus is calculated as:

S=M/F

S--> section modulus

M--> Maximum Bending moment

F--> Allowable stress

The maximum bending moment is computed for a plate supported by beams underneath. Assuming there are 2 supporting beams, can required section modulus for each be divided by 2 to choose a beam section having section modulus S/2?

Answer 1

Your question is a bit confusing to me, but I think the answer might be yes.  If you do not have the space (Depth) to allow a single structural member with the required section modulus to be used at a particular position, shallower members could be used whose combined modulus , when added, is equal or greater than the requirement. You will actually be dividing the load between the two. Usually the two members are identical.

Sometimes a structural member which is a little lacking in modulus, can have reinforcing added to the top and bottom flanges to increase its section modulus.

If a particular shape is not adequate, you may use a different shape, for instance an H beam instead of an I beam.